Method of making black iron sheet metal containers



June 29, 1943 f N. H. GoLDswoR-rHY 2,322,845 uE'rEonoE man@ BLACK mon SHEET METAL CONTAINERS a Filed July 5, 1940 Waff/vra@ irrafm/fye MMM Patented .lune 29, 1 943 METHOD F MAKING BLACK yIRON SHEET METAL CONTAINERS Norman H. Goldsworthy, Syracuse, N. Y., assigner to Continental Can Company, Inc., New York,

N. Y., a corporation oi' New York Application .my s, 1940, semi No. 343,861

(Cl. 113-120) The invention relates to new` and useful im- 4 2 Claims.

provements in the method of making a sheet metal can from black iron.

An object of the invention is to provide a method of making a sheet metal can of the-above type wherein the side seam, at least, is rendered hermetic by metal brazing.

Another object of the invention is to provide a method of making a sheet metal can wherein the side and end seams are rendered hermetic by metal brazing.

A further object of the linvention is to pr vide a method of making a can of the above type, wherein the brazing material is secured to the blank or blanks from which the can is made and is placed in the seams during the forming and assembling of the parts to form the seam.

A stillfurther object of the invention is to provide a method of making a can body of the above type, wherein the brazing material is meltn ed and caused to flow Iby capillary attraction throughout the limits of the side seam by heat applied to the seam in a non-oxidizing atmos` phere.

These and other objects will in part be obvious and will in part be hereinafter more fully described.

In the drawing- Figure 1 is a plan view of a body blank cut to shape for the making of a body;

Fig. 2 is a similar view showing the edge portions bent to form interlocking hooks;

Fig. 3 is a horizontal sectional view through the side seam in the region of the hooks after the hooks have been interlocked and bumped;

Fig, 4 is a sectional view through the lap portions of the side seam;

Fig. 5 is a view on the line 5-5 of Fig. l0, after the body has been 'heat treated and the edge portions joined by a metallic bond;

Fig. 6 isa transverse sectional view through the lap portions of the side seam after said lap portions have been bonded;

Fig. 'l is'a sectional view 'through one end` body with the bottom end attached embodying the improvements.

The present invention has to do with the v'methcd of making can bodiesfrom black iron A Vand the can produced thereby. It is thought that ployment of the invention in the making of a can from black iron. The method of making the can body will iirst be described, and then the method of attaching the ends thereto.

The can body blank indicated at'i in the drawing is cut from a sheet of black iron to suitable shape for the forming of a can body. It is notched as indicated at 2, setting oil the portion which is to form the outer hook 3. It is also provided with slits 4 adjacent each end of the blank, settingof! the portion which is to be bent so as to form the inner hook 5. lBefore notching i and cutting the blank, a thin strip of copperl is secured to the blank in the region where the inner hook is to be formed.

This strip may be of any `desired width, but as shown it is of sufficient width to cover the entire inner surface of the inner hook and over- -lie a portion of the body blankadjacent the hook. This nlm of copper may be secured by an H adhesive or in any suitable way to the body blank. All that isnecessary is to secure'it to' the blank so that it will retain its position on the blank as the blank passes to the notching, slitting and hook-forming stations, and also to the body forming and bumping station.

Instead of applying the copper in the form of a lm, it maybe applied in the form of a paste,

that is, the Vcopper ground up and mixed with al suitable adhesive for amxing the copper to the blank. It may also be applied by electro-deposition. The essential thing isthat a strip of copper shal1 be applied to the blank in the region of the edge portion which is to form one of the hooks of the side seam. This strip is also extended so as to lie between the lap portions at the ends of the hooks. While the copper strip is shown as applied to the inner hook, it may be applied to the edge portion o'f the blank which is to form lthe outer hook. Here again, the essential feature consists in the placing of the copper strip so that it will be disposed within the seam when the parts are interlocked.

In Fig. 2 of the drawing, the body blank `is shown as provided with hooks 3 and 5. After the body blank is thus formed, it is then shaped into a can body and the hooks interlocked and bumped in the usual manner. Fig. 3 shows a section through the interlocked hooks, after the both the method and the article producedrwill be better understood by a description of the embumping operation. It will be 'noted that the copper strip 6 extends throughout a considerable portion of the seam. The copper strip 6 also extends between vthe lap portions 1 and 8 at the end of the side seam. Y

The invention may be applied to the making of the side seam only of the canbody and the ends secured thereto in the usual `way by rolling the end ange and the body ilange together with a sealing composition into a double seam. lThe same method -of making the side seam may black iron and shaped so that it is ready for attachment to the can body by seaming. `A` thin copper'annulus 9 is secured in the channel -of the end flange I of the can end Il. Thecan body which is indicated at I2, isprovided with a flange I3 in the usual manner. `The flange of thecan end I0, and the fiangel3 of the can bodlr are rolled into a seam I4 as shown in Fig. 8. It

is noted that the 'copper annulus extendsv throughout the greater portion of the seam I4. This copper annulus 9 may be formed from a thin sheet of copper, or Vby mixing copper with paste, or may be electro-deposited'upon the can end. Here again, the essential feature is that the copper shall be attached to the end so as,to become a unit therewith for handling and seaming 'purposes'. y

' After the can body has beenforrned in the manner above described and an end attached thereto, then the formed can is placed in an electric furnace lprovided with a non-oxidizing atmosphere, which furnace is heated t'o a temperature of approximately 2100 F. The cans may be placed on endless conveyors and passed into and` through the furnace. This will cause the copper to melt as the temperature of the furnace is above .the melting temperature of copper. It is, however, below the melting point of black iron. The non-.oxidizing atmosphere prevents oxidation ofthe metals and frees them' from any already formed oxides, thus preparing the surface to be wetted by the molten brazing metal. The copper when it is melted will mlove by capillary attraction throughout all parts of seams together, it will be understood that other brazing materials might lbe used in the place v-of copper, which brazing materials melt at a temperature lower than that at which the black iron melts., It yis preferred, however, that the brazing material shall melt at a temperature near that ofthe black iron, so that the heat treatment of the metal parts in a non-oiddizinnz atmosthe seams forming a bonding alloy with the iron.

The cans are then passed into a cooling chamber having a controlled non-oxidizing atmosphere, where the bonding metal is cooled and set.

' In this manner, the parts are joined by a tight thereto by joining the same to the body by double seaming with a sealing composition, then'the body after the copper strip `has been attached thereto, and the hooks formed` and bumped, is

placed in the furnace and treated in the manner above stated. The lbody may beilanged before or after the heat treatment. lIn either. case, the copperwill melt and flow by capillary attraction throughout the entire of the side seam, metal bonding the parts together :and forming an hermetic seam.. l

While the invention is shown as applied to a can body having a lock and lap side seam, it will be understood that lit may be applied to a lap seam can body wherein the edge portions of the body blank are lapped., The copper metalufor brazing is placed between the lap portions of the side seam and the lap portions may be held properly placed relative to each other after the body is shaped and in contact with the brazing metal, by spot welding. Y

While copper has been referred to as the brazing material for bonding the metal of the phere will free the metal parts from formed oxides and thus prepare the surface to be joined. Furthermore, when the brazing material melts at a temperature near that of the black iron, a-

rmer bonding alloy of brazing metal and iron can be produced and a stronger joint obtained.

-body from black iron including cutting a blank from a sheet of metal of proper size to form a can body havin-g a side seam comprising interlocked hooks and lap sections at the ends of the hooks, attaching a thin strip of brazing material having a melting temperature near that of black iron to the edge portions of the blank so that said strip wll'be disposedl within the' hooks and extend between the lap sections in the formed can body, cuttingvand notching said'blank, bending the edg'e portions to form the hooks, shaping the blank into a can body and joining the hooks and bumping the same so as to enclose the brazing strip in the bumped seam and heating the formed body in a non-oxidizing atmosphere to a -temperature suliicient to melt the brazing material and cause the same to flow by capillary attraction throughout the entire limits of the seam and form an alloy with the black iron firmly uniting the edge portions of the body blank.

2. The method of making 'a sheet metal can from black iron including 'cutting a blank from a .sheet of metal of proper size to form a can body having a side seam comprisinginterlocked hooks and lap sections at the ends of the hooks,

' attaching a thin strip of brazing material having a melting temperature near that of black iron tothe edge portions of the blank so that said strip will Ibe disposed within the hooks and extend between the lap sections in the formed can body, cutting and notching said blank, bending the edge portions to form the hooks, shaping the blank into a can body and joining the hooks and bumping the same so as to enclose the brazing strip in the bumped seam, flanging the ends of the can body, die shaping a black iron blank to form a can end adapted to be double seamed to the flanged end of the can body, attaching a similar strip of brazing material to the inside of the channel of the can end, double seaming the bottom end to the can body so as to join the end to the body and enclosing the brazing strip within the double seam, andheating the formed can in .a non-oxidizing atmosphere to a temperature sufficient to melt the brazing material and cause the same to ow by capillary attraction throughout the limits of the side seam and.

throughout the limits of the double seam.

` NORMAN H. GOLDSWORTHY. 

